There's usually a symbol next to the port. If it has the ⚡ symbol then yes, it can be charged through it. here's an image for reference

@Broccoli Cobalt  Glad you found my post useful! If your laptops are designed for a 65W power source, then you shouldn't be considering USB-C displays that only provide 45W unless you also plan to keep the laptop's AC adapter directly attached as well.  Otherwise, while you won't DAMAGE anything by giving your laptop an undersized power source, you will create a subpar experience for your users.  First, the laptop will display a warning about an undersized power source every time it boots while connected to one, which will be an annoyance.  But worse, if a laptop designed for a 65W power source is only fed 45W, the laptop will try to operate within that reduced power budget by doing things like reducing its battery charging speed and reducing its CPU and GPU performance.There are several USB-C displays on the market now that provide 65W or even 90W (although as mentioned above, as of this writing you won't get more than 65W over USB-C to a Dell system unless it's from a Dell source).  I would recommend that you consider one of those options.  Also keep in mind the note above about the USB-C cable coming into play if you want to go above 60W.  If the displays you buy supply more than 60W and come with a USB-C cable, then it's a safe bet that the included cable will be rated for up to 100W.  But if you'll be buying USB-C cables separately, you'd want a USB-C cable that supported DisplayPort Alt Mode for video and USB PD up to 100W, like this one.

It's not dangerous and this won't affect the functionality. If you ever see metal strands from the internal wires then stop using it immediately.